ENGINE SMOKING UPON START UP

I have recently experienced every time I start it up, to have blue-white smoke come out of the exhaust. The place where I bought it told me that is what every lexux does at that age and it is supposed to be sending extra gas somehow to heat it up for when it's cold. It has been in the 80-90's everyday for a month here, no cold!

I think they are full of crap. I did some reading on the net and it looks like this could be a valve stem problem, or sludge build up? I know that color of smoke which is the worst smell reminds me of a buddies car which eventually seized up.

Can you tell me what you think is happening here. It's a Lexus 2002 rx 300 awd.